1. Field of the Invention
The present invention relates to a semiconductor device, and in particular, to a semiconductor device in which temperature increase in operation is suppressed.
2. Description of the Background Art
Recently, a semiconductor device of high performance has been demanded to meet various needs. Accordingly, an effort is being made to manufacture a semiconductor device of smaller size, higher density and higher integration. As the size of the semiconductor device is made smaller, an amount of heat produced from the same in operation has increased.
When the amount of produced heat increases and a temperature of the semiconductor device is raised, the semiconductor device would fail to perform a desired operation. Therefore, the semiconductor device is provided with a measure to dissipate heat or control temperature. Typically, for example, a heat radiating fin is attached, or a cooling fan is provided to the semiconductor device, to forcibly cool the same.
A conventional semiconductor device, however, has had a disadvantage as described below. As mentioned above, though cooling of the semiconductor device has been achieved by attaching a heat radiating fin and providing a cooling fan, it is becoming difficult to obtain sufficient cooling effect as the semiconductor device is made smaller. In addition, since the heat radiating fin and the cooling fan are additional members, providing the same has caused an increase of production cost.
The present invention was made to solve the above-mentioned problems. An object thereof is to provide a semiconductor device in which cooling effect can readily be obtained without increasing production cost.
A semiconductor device according to an aspect of the present invention has a prescribed element, a conductive region and a thermoelectric converting element. The prescribed element is formed in a prescribed region on a main surface of a semiconductor substrate, and includes an impurity region of a first conductivity type and an impurity region of a second conductivity type. The conductive region is electrically connected to the prescribed element. The thermoelectric converting element is formed on the main surface of the semiconductor substrate, has one end side arranged in the vicinity of the prescribed region to absorb heat produced in operation of the prescribed element, and has the other end side arranged in a region producing smaller amount of heat among regions of the semiconductor substrate. The thermoelectric converting element includes a semiconductor region of the first conductivity type and a semiconductor region of the second conductivity type, a first interconnection portion, a second interconnection portion and a third interconnection portion. The semiconductor region of the first conductivity type and the semiconductor region of the second conductivity type are respectively formed on the main surface of the semiconductor substrate, extending from the vicinity of the prescribed region to the region producing smaller amount of heat. The first interconnection portion is electrically connected to the semiconductor region of the first conductivity type and the semiconductor region of the second conductivity type on the one end side. The second interconnection portion is electrically connected to the semiconductor region of the first conductivity type on the other end side. The third interconnection portion is electrically connected to the semiconductor region of the second conductivity type on the other end side.
With such a configuration, heat produced in the prescribed element in operation will be absorbed by the thermoelectric converting element formed on the main surface of the semiconductor substrate and having the semiconductor region of the first conductivity type, the semiconductor region of the second conductivity type and the first to third interconnection portions. Thus, the semiconductor device can be easily cooled without externally providing additional cooling members such as a fin or a fan, as in a conventional semiconductor device. In addition, this thermoelectric converting element can be formed, without additional new steps, simultaneously with the prescribed element. Thus, a semiconductor device with high cooling effect can readily be obtained without increasing manufacturing cost.
Specifically in the thermoelectric converting element, preferably, the semiconductor region of the first conductivity type is formed simultaneously with the impurity region of the first conductivity type; the semiconductor region of the second conductivity type is formed simultaneously with the impurity region of the second conductivity type; and the first interconnection portion, the second interconnection portion and the third interconnection portion are formed simultaneously with the conductive region.
In addition, with respect to the thermoelectric converting element, a power supply portion is preferably provided for providing a direct current from the second interconnection portion through the semiconductor region of the first conductivity type, the first interconnection portion and the semiconductor region of the second conductivity type toward the third interconnection portion.
Thus, heat produced in the prescribed region having the prescribed element formed therein will be dissipated by the thermoelectric converting element to the region producing smaller amount of heat, and cooling of a heat producing portion in a semiconductor device is achieved.
Moreover, an electromotive force measuring portion connected to the other end side of the thermoelectric converting element, and a temperature control portion connected to the power supply portion and controlling heat absorption by the thermoelectric converting element by adjusting a current provided to the thermoelectric converting element based on the electromotive force detected by the electromotive force measuring portion are preferably provided.
Thus, the current provided to the thermoelectric converting element is adjusted in accordance with a temperature in the prescribed region, and more appropriate and efficient cooling can be achieved.
Meanwhile, the electromotive force produced in the thermoelectric converting element by absorbing the heat is preferably used for driving other elements formed on the semiconductor substrate.
In this case, heat produced in the prescribed region is converted to thermal electromotive force, to suppress temperature increase therein, and the heat producing portion in the semiconductor device is cooled. In addition, using the electromotive force for driving other element can save power consumption.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.